InterPro domain: IPR000253

The forkhead-associated (FHA) domain [ 1 ] is a phosphopeptide recognition domain found in many regulatory proteins. It displays specificity for phosphothreonine-containing epitopes but will also recognise phosphotyrosine with relatively high affinity. It spans approximately 80-100 amino acid residues folded into an 11-stranded beta sandwich, which sometimes contain small helical insertions between the loops connecting the strands [ 2 ].

To date, genes encoding FHA-containing proteins have been identified in eubacterial and eukaryotic but not archaeal genomes. The domain is present in a diverse range of proteins, such as kinases, phosphatases, kinesins, transcription factors, RNA-binding proteins and metabolic enzymes which partake in many different cellular processes - DNA repair, signal transduction, vesicular transport and protein degradation are just a few examples.

1. The FHA domain: a putative nuclear signalling domain found in protein kinases and transcription factors. Trends Biochem. Sci. 20, 347-9
2. The FHA domain. FEBS Lett. 513, 58-66